Gun nozzle for adding lead pellets to liquid steel



July 7, 1959 P. H. SMITH 2,893,716

GUN NOZZLE FOR ADDING LEAD PELLETS TO LIQUID STEEL Filed Jan. 14, 1958 GUN NOZZLE FOR ADDING LEAD? 1 To LIQUID STEEL invention relates toan improvement infor ma ma new orm. such a di a n a steel, and more particularly to a'no'z'zle for sucli'agun wherein the metal impelling force is supplied by a head of gas upon a remote source of the metal to be added.

This is a continuation-in-part of my copending application Serial No. 436,477, filed June 14, 1954, now abandoned.

The addition of a metal such as lead to steel has been disclosed by earlier patents. Inasmuch as most additive metals such as lead are volatile to a considerable extent at the high temperatures involved in molten steel and are easily oxidized, it is important that the metal to be added be quickly and uniformly distributed throughout the steel and that the mixing operation be completed in as short a time as possible.

It is also important that the metal be uniformly distributed to accomplish maximum good with a minimum use of the added metal.

Until recently lead, for example, had been introduced to molten steel from jet nozzles in which the impelling force applied to the lead was supplied by an air or gas jet. Recently a gun has been developed in which the lead is supplied in small pellets fed from a hopper, which hopper is connected to the gun nozzle by a conduit such as a hose, and which hopper is maintained under a substantial head of gas pressure. This method supplied very much less gas in comparison to the amount of lead than the previous guns, and has proved to be extremely effective in distributing lead uniformly throughout the steel.

Such guns which I here designate as pressure guns to distinguish from jet guns, however, have a difficulty in that for some reason or other, there is a tendency in them, which was lacking in the earlier guns, to establish a condition of flutter at the nozzle.

I have discovered that this diiliculty may be overcome by the use of a small wire or baflle adjacent the nozzle opening and extending transversely of it.

The invention is illustrated in the drawings, in which:

Figure 1 is a somewhat diagrammatic elevational view partially broken away of a gun system;

Figure 2 is a cross section through the gun nozzle taken longitudinally thereof; and

Figure 3 is a transverse section taken along line 3-6 in Figure 2.

As indicated in the drawings, a hopper is supplied for primary inspection of small lead pellets. A valve 11 controls the feeding of lead therefrom into the storage hopper 12. A supply of lead is maintained in the storage hopper preparatory to use. At this stage, valve 14 is opened to supply gas under pressure to the top of the hopper 12. The small lead pellets or shot being substantially round and preferably of substantially uniform size, flow like a fluid under the influence of the pressure through the conduit or hose 15 and the control valve 16 to the nozzle 17. It is of course understood by flexible connections that either the hose is flexible or the connec- 2,893,716 Patented July 7', 1959 2 tions are sufliciently flexible to permit the nozzle to be directed as desired.

1 The nozzle 17 has an interior chamber 18 substantially. the diameter of thehose which connects with a tapering throat 19 to the mouth 20. The walls of the mouth are preferably. parallel and its diameter is a small frac-v tion of that of the main chamber of the nozzle. The cross-sectional shape of the inside of the nozzle is the same throughout the tapered length.

Toward the rear of the tapering section, a thin baflle 21 is' provided extending from one side of the .throat to the other. This bafile may be in the form ,ofa wire or a thin vein. For example, in a nozzle having a main chamber 1 inch in diameter tapering through a throat. 3 to '4 inches long to a mouth inch in diameter, a wire toi ii inch in diameter and 1 to 1% inches fromthe' mouth has proved quite satisfactory. I

When this Wire or vein is in place, slugging or packing or fluttering is avoided. Furthermore, greater recovery of lead is obtained, i.e., a greater amount of lead mixed into the steel and less gas is required to accomplish this. The operation of slugging may be described as a condition during which mass flow of lead from the nozzle ceases for a short interval of time and then commences with increasing velocity up to a point Where it ceases again.

The stationary wire or baflle deflects the gas and pellets and provides a component of force at right angles to the direction of flow passing through the center of the cross section. It has been found that it works most efliciently in general at a point about one third of the distance from the beginning of the taper to the end thereof.

If the baffle is of irregular shape, it should be placed so that the shortest or thinnest edge faces the flow of material. It is believed that the wire in dividing the flow impedes it in such a Way as to provide a constant mass flow velocity, thereby eliminating the slugging.

The foregoing detailed description and the particular metal, i.e. lead, has been given for clearness of understanding only and no unnecessary limitations should be understood therefrom as modifications will be obvious to those skilled in the art.

I claim:

1. A gun nozzle for supplying granular material under head pressure at a constant mass flow velocity comprising a nozzle smoothly converging internally between the receiving end and a mouth which is smaller than the receiving end, the cross-sectional shape of the inside of the nozzle being the same throughout the tapered length, and said nozzle having in the converging area a transverse fixed member which substantially inhibits fluttering in the flow of granular material from the nozzle.

2. The nozzle of claim 1 in which the member has a thin linear edge normal to the direction of allow of granular material.

3. A gun nozzle for supplying granular material under head pressure at a constant mass flow velocity comprising a nozzle converging smoothly internally from the receiving end to a mouth which is smaller than the receiving end, the cross-sectional shape of the inside of the nozzle being circular, said nozzle having in the converging area a transverse fixed rod-like member.

4. Gun means for supplying metal pellets to molten steel comprising a closed hopper and a means for supplying gas under pressure to the hopper, a conduit communicating with the hopper and having a nozzle of circular cross-section at its terminal end, the conduit being substantially smaller in cross-section than the hopper, said nozzle having a mouth, the entire internal surface of the nozzle being smoothly tapered toward the mouth,

there being a transverse rod-like member in and extending across the tapered section so placed as to substantially inhibit fluttering in the flow of metal pellets from the nozzle.

5.. Apparatus as set forth in claim 4 in which the rodlike member extends across the tapered section and is approximately one-third of the distance fr'orn'the beginning of the tapered section to the mouth.

6. A gun nozzle for supplying granular material under head pressure comprising a nozzle housing having: a chamber with parallel interior walls adapted to communicatewith a hose of substantially equal 7 diameter, a mouth smallerthan the chamber, a smoothly. tapered section extending from the chamber to. the mouth, the cross sectional shape of the inside of the nozzle being circular, and a transverse rod-like member." in thetapered section for controlling fluttering of granular material passing from said nozzle.

7'. A gun nozzle for supplying granular materialrunder I head" pressure at a constant mass flow velocity compris ing a nozzle converging smoothly internally the rivriig endto a vvliich' is smaller than the' receivingaend the cross sectional shape of the inside. of

the nozzle being circular and having a receiving end of about one inch diameter internally and a mouth of about one-quarter inch diameter, said nozzle having in the converging area a transverse fixed rod-like member of about one-eighth inch diameter.

' of this patent UNrTED" STATES PATENTS 11,6: fieuejj" a M9121, 19 12 1,496,635 'Higre June's, r924 1,9Q 2 2 Q2. Mar. 21, 1933 130E990 Apr. 18, 1933 2,562,930 i Aug. 7, 1951 2,602,701 Walter July 8, 1952' FOREIGN PATENTS 6182521 Sept '1, 19:49

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent Nos 2,893,716 July '7, 1959 Phillip Hartley Smith It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction and that the said Letters Patent should read as corrected belowo Column 4, line ll, list of references cited, under the heading "UNITED STATES PATENTS", for the patent number "1,036,630" read 1,036,638

Signed and sealed this 8th day of March 1960.

Attest:

RL? AXLINE ROBERT c. WATSON Attest ng- Officer v Cormiissioner of Patents 

